This is the brake lever mount that gets brazed to the handlebars. Sometimes the biggest problem making a part is figuring out how to hold it. By cutting this part off as the very last operation, there's always a big chunk to hold onto for the boring, milling, drilling, tapping and slotting.
Pacific Bending and Machine bent all the frame tubes and did the bars too. It's a nice compound bend, copied from an original Columbia bicycle from the late 1800's. The handlebar stem is four pieces of steel brazed together, and it too will look like a lug after a nice coat of nickel.
These are most, but not all, of the fittings needed to build one steamer.
Each boiler gets (55) 12" long type K (refridgeration) copper tubes with a 5/8" OD.